Welcome and thank you for adopting! Once approved, post your concerns in Training section. You should go ahead and start the "2 weeks, give em a break!" thread in training as well as read up on "introducing a new dog" thread. They are both stickies and it is not too late to do. Also, check out the NILF thread (aka nothing in life is free, also referred to as NILIF) in training. Clicker/marker training would probably work great for you too.

Pics can be posted via Tapatalk app from your phone, or via a host site like Photobucket from your computer. There is a sticky at the top of Intros for how to do it from your computer.

The dominance stuff is nonsense when it comes to all dogs, not just pitbulls.

I also wouldn't follow the two week shut down necessarily as its meant for adult dogs, not pups.

You need to intervene in the interactions between the two of them if the little dog is "tormenting" him. You have said that you are worried about the pup, but it would seem that your small dog needs some work too.

Also, don't buy in to any "breed specific" advice you get-- without knowing the parents, what you have is a mutt. There's no guarantee that she even IS a Pitbull. So take her for what she is, an individual.

For now I would keep their interactions short and sweet and separate them when things get too rambunctious. Let them interact during activities and times when they are less likely to get wound up, such as when you are out on a walk.